Chief Radiographer Bjarte Snekvik and Associate Professor Alexander Olsen illustrate how their study subjects perform the fMRI task (the person in the photo was not a study participant). Study participants used specially designed response buttons (as shown) and could view the task through video goggles. Photo: Geir Mogen, NTNU

How very low birth weight affects brain development

Children born with very low birth weights are at an increased risk of cognitive, emotional and behavioral problems throughout their lives. But what exactly happens in the brain to cause these problems?

Every year, one in ten babies worldwide are born too early. That’s roughly 15 million children, according to the World Health Organization. When children are born too soon, they are at higher risk of mental and physical disabilities, especially if they weigh less than 1500 grams at birth.

While three-quarters of these preterm births are thought to be preventable, sometimes it’s simply not possible. That last fact has researchers like Alexander Olsen, an associate professor at the Norwegian University of Science and Technology (NTNU), working to better understand the consequences of very low birth weights on cognitive development.

Olsen is director of the Clinical Neuroscience Laboratory at the university, which focuses on investigating the consequences of brain injury and disease, in part by using advanced neuroimaging. Olsen is also a specialist in clinical neuropsychology and holds a position at St. Olavs Hospital, where he works with assessments and clinical follow-ups of patients with acquired brain injuries.

While Olsen’s primary research interest is traumatic brain injury, his research using fMRI on this topic attracted the attention of colleagues in Trondheimwho had been working with very low birth weight individuals and brain development.

Long-term study offers new insights

When Olsen was a research fellow at NTNU’s Medical Imaging Laboratory, he worked closely with the head of the Trondheim fMRI Group, Asta Håberg, to expand his research to include a collaboration with the Centre for Early Brain Development, which is conducting a long-term study of individuals with low birth weight. The collaboration also grew to include researchers from the University of Southern California’s Imaging Genetics Center at the Stevens Institute for Neuroimaging and Informatics.

“The idea emerged that a lot could potentially be learned through studying these groups in parallel, because they are both typically characterized by alterations in the white matter of the brain, although for different reasons,” he said. The white matter is important because it helps provide connectivity between different areas of the brain.

“Comparing how brain function adapts differently to pre- and perinatal injuries and those acquired as adults could provide important information on how the brain works in general,” he added.

Cognitive control a problem

Olsen and his colleagues wanted to see how the brains of very low birth weight individuals differed from their normal birth weight cohorts when it came to cognitive control, and the ability to think proactively or reactively about different tasks. That’s because cognitive control dysfunction is one of the biggest problems facing very low birth weight individuals, Olsen said.

Study participants were told to press a button when they saw a letter in their video goggles, except when the letter was X. This task enabled researchers to see which parts of the participants’ brains were engaged when they did the task. Illustration courtesy Alexander Olsen/NeuroImage

“Cognitive control is related to the goal-directed regulation of thoughts, actions and emotions,” Olsen said. “You have to effectively organize and quickly use your mental capacities in a flexible way to cope with the world. A lot of individuals born with very low birth weight have problems with that.”

To study this question, the researchers relied on a group of very low birth weight individuals who were born between 1986 and 1988 in Trondheim, Norway. These individuals had already participated in MRI studies in Trondheim when they were 1, 5, 14 and 20 years old. Thirty-two individuals between 22 and 24 years of age from this group participated in Olsen’s study and were matched with same-aged controls that had normal birth weights.

For the first time in this cohort, the researchers used fMRI imagery to conduct their work, which allows them to see activation in different parts of the brain as study subjects are engaged in a task.

In this study, participants looked at a computer screen while in the scanner and were shown a series of random letters. Their task was to press a button as quickly as possible when they saw a new letter pop up on the computer screen, except when the letter was “x”. The most common response was to press the button, because the letter “x” was only presented 10% of the time.

“You need two different types of cognitive control to complete this assignment,” Olsen said. “So that simple task gave us a lot of information.”

Proactive and reactive systems

The orange-yellow areas show where low birth weight individuals had less proactive cognitive control (Stable Task-Set Maintenance) activation in the brain. The blue/light blue areas show where they had more reactive cognitive control (Adaptive Task Control) activation, compared to the normal birth weight control group. Image courtesy Alexander Olsen/NeuroImage

The brain is constantly working to create meaning out of the flood of information that comes at us every waking minute of our day, Olsen says. Researchers have identified two different processes the brain relies on to achieve this task: a proactive cognitive control function, and a reactive function.

Proactive cognitive control relates to proactively working on a task — like the task given to study participants in the MRI scanner. They knew that most of the time they had to press the button, and they mentally prepared, in a proactive way, to identify new letters as each letter popped up, and to find a balance so that they could respond as quickly and accurate as possible.

But the appearance of the “x” on the screen required a different reaction, Olsen said. “The reactive system kicks in when something happens that is not expected,” he said. “Then you need to adapt your behaviour and react to the new information. You have to throw away your old plan and come up with a new plan.”

The difference between the two different cognitive systems turned out to be important in explaining other behavior in the very low birth weight individuals, the researchers found.

More reactive, less proactive

The very low birth weight study participants completed the tasks as well as the normal birth weight participants, the researchers found. But they used different cognitive functions to do so, Olsen said.

“What we found was that the preterm group had less proactive brain activation and were more reactive compared to the normal birth weight control group,” Olsen said.

This hyper-reactive brain activation signature was accompanied with poorer white matter organization in the brain, and was associated with lower fluid intelligence and anxiety problems. Researchers define fluid intelligence as the ability to think abstractly, identify relationships and solve novel problems.

The blue colours represents two white matter tracts in the brain that are particularly important for cognitive control function. Regions in red-green (and indicated with arrows) show parts of the brain where low birth weight individuals had poorer white matter organization compared to the normal birth weight control group. Image courtesy Alexander Olsen/NeuroImage

This difference meant “their brains reacted as if they were encountering something new each time,” he said. “It suggests their brains are hypervigilant due to suboptimal organization of the central nervous system. One interpretation is that they are less prepared and more surprised each time, which might create more anxiety problems.”

Making sense of anxiety

As both a researcher and a clinical neuropsychologist, Olsen thinks about the potential applications of his research findings.

“As a clinician, this is particularly interesting,” he said. “It makes sense as to why, when you meet some of these individuals as patients, they are experiencing problems with cognitive control function, and having this tied to other emotional problems.”

Although the fMRI isn’t a practical tool for a clinical setting, the researchers’ findings can provide a backdrop for better understanding patients in this group, he said.

“When we work with people with cognitive dysfunction or anxiety problems, we are trying to help them be more proactive in how they prepare for certain situations, so they don’t have to rely on reactive problem solving as much,” Olsen said. “When you work with cognitive behavioral therapy or cognitive rehabilitation, you work on getting structure into people’s lives so they don’t have to rely too much on their online cognitive control processing. Creating structure and routine in your life frees up cognitive control resources that can instead be more effectively used for dealing with those things that can’t be planned for.”

Researchers at the Kavli Institute for Systems Neuroscience have discovered a network of brain cells that expresses our sense of time within experiences and memories. The area of the brain where time is experienced is located right next to the area that codes for space.

A century-old theory still affects how we treat our babies and can affect children’s learning, according to an NTNU neuroscientist.

MORE NORWEGIAN SCITECH NEWS

LOADING CONTENT

Privacy Policy

The Privacy Statement is about how this website collects and uses visitor information. The statement contains information that you are entitled to when collecting information from our website, and general information about how we treat personal data.The legal owner of the website is the processing officer for the processing of personal data. It is voluntary for those who visit the web sites to provide personal information regarding services such as receiving newsletters and using the sharing and tip services. The treatment basis is the consent of the individual, unless otherwise specified.

1. Web analytics and cookies (cookies)

As an important part of the effort to create a user-friendly website, we look at the user pattern of those who visit the site. To analyze the information, we use the Google Analytics analysis tool.Google Analytics uses cookies (small text files that the site stores on the user's computer), which registers the users' IP address and provides information about the individual user's online movements. Examples of what the statistics give us answers to are; how many people visit different pages, how long the visit lasts, what websites users come from and what browsers are used. None of the cookies allow us to link information about your use of the site to you as an individual.The information collected by Google Analytics is stored on Google servers in the U.S.. The information received is subject to the Google Privacy Policy.An IP address is defined as a personal information because it can be traced back to a particular hardware and thus to an individual. We use Google Analytics's tracking code to anonymize the IP address before the information is stored and processed by Google. Thus, the stored IP address can not be used to identify the individual user.

2. Search

If the webpage has search function, it stores information about what keywords users use in Google Analytics. The purpose of the storage is to improve our information service. The search usage pattern is stored in aggregate form. Only the keyword is saved and they can not be linked to other information about the users, such as the IP addresses.

3. Share / Tips service

The "Share with others" feature can be used to forward links to the site by email, or to share the content of social networking. Tips for tips are not logged with us, but only used to add the tips to the community. However, we can not guarantee that the online community does not log this information. All such services should therefore be used wisely. If you use the email feature, we only use the provided email addresses to resend the message without any form of storage.

4. Newsletter

The website can send out newsletters by email if you have registered to receive this. In order for us to be able to send e-mail, you must register an e-mail address. Mailchimp is the data processor for the newsletter. The e-mail address is stored in a separate database, not shared with others and deleted when you unsubscribe. The e-mail address will also be deleted if we receive feedback that it is not active.

5. Registration, form

The website may have a form for registration, contact form or other form. These forms are available to the public to perform the tasks they are supposed to do.Registration form is for visitors to sign up or register.Contact form is for visitors to easily send a message to the website's contact person.We ask for the name of the sender and contact information for this. Personal information we receive is not used for purposes other than responding to the inquiry.The form is sent as email via Mailgun as a third party solution. The entire submission will be stored at Mailgun for 24 hours. Between 24 hours and 30 days, only mailheader is stored before the submission is deleted after 30 days. The reason for this storage is to confirm whether emails are sent from the website and forwarded to the correct recipient.Once the email is received by the recipient, it is up to the recipient to determine the data processing needs of the email.

6. Page and service functionality

Cookies are used in the operation and presentation of data from websites. Such cookies may contain language code information for languages ​​selected by the user. There may be cookies with information supporting the load balancing of the system, ensuring all users the best possible experience. For services that require login or search, cookies can be used to ensure that the service presents data to the right recipient.